Contraceptive Pill: Cancer Protection

Jan 24, 2008 -- Oral contraceptives cut women's risk of ovarian
cancer for more than 30 years after they stop taking them -- giving the
pill a net anticancer effect.

Each five-year interval of oral contraceptive use cuts a woman's
ovarian cancer risk by up to 29%. The longer a woman uses the
pill, the lower her risk of ovarian cancer, find Valerie Beral, MD, director of
the Cancer Research Epidemiology Unit at Oxford University, England, and
colleagues.

"We can say the longer women take it, the longer the protection, which
lasts 30 years after they stop," Beral tells WebMD. "This does outweigh
any other cancer risk from taking the pill. So the net effect is to reduce
cancer overall. Women on the pill do not need to worry they are putting
themselves at long-term risk of cancer."

It's been known for a long time that oral contraceptives cut a woman's
lifetime risk of ovarian cancer. It's also known that the drug increases a
woman's risk of breast and cervical cancer while she's on the pill. Now Beral and
colleagues have been able to put numbers on these risks.

"In breast and cervical cancer there is increased risk, but these
effects disappear and are not persistent after a woman discontinues oral
contraceptives," Beral says. "Whereas ovarian cancer protection lasts
for decades -- into the ages when this cancer becomes more common for a
woman."

Pill's Anticancer Effect 'Definitive'

An astonishing amount of data went into the study. Beral and colleagues
combined data from 45 high-quality studies that included detailed data on
23,257 women with ovarian cancer and on 87,303 women without ovarian
cancer.

They calculate that over the 50 years oral contraceptives have been on the
market, the drugs have prevented at least
200,000 ovarian cancers and prevented 100,000 deaths. Because use of the pill
is increasing, they predict that the pill will prevent at least 30,000 cases of
ovarian cancer each year for the next several decades.